Power generation system having compressor creating excess gas flow for supplemental gas turbine system

ABSTRACT

A power generation system may include a generator; a gas turbine system for powering the generator, the gas turbine system including a turbine component, an integral compressor and a combustor to which air from the integral compressor and fuel are supplied, the combustor arranged to supply hot combustion gases to the turbine component, and the integral compressor having a flow capacity greater than an intake capacity of at least one of the combustor and the turbine component, creating an excess air flow. A first control valve system controls flow of the excess air flow along an excess air flow path to a supplemental gas turbine system. The excess air flow may be combusted with a fuel and supplied to the supplemental gas turbine system. An eductor may be positioned in the excess air flow path for using the excess air flow as a motive force to augment the excess air flow with additional gas.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. application numbers:application Ser. No. 14/662,814, application Ser. No. 14/662,822,application Ser. No. 14/662,828, application Ser. No. 14/662,847,application Ser. No. 14/662,851, application Ser. No. 14/662,858,application Ser. No. 14/662,751, all filed on Mar. 19, 2015.

BACKGROUND OF THE INVENTION

The disclosure relates generally to power generation systems, and moreparticularly, to a power generation system including a gas turbinesystem having a compressor creating an excess air flow for use with asupplemental gas turbine system.

Power generation systems oftentimes employ one or more gas turbinesystems, which may be coupled with one or more steam turbine systems, togenerate power. A gas turbine system may include a multi-stage axialflow compressor having a rotating shaft. Air enters the inlet of thecompressor and is compressed by the compressor blade stages and then isdischarged to a combustor where fuel, such as natural gas, is burned toprovide a high energy combustion gas flow to drive a turbine component.In the turbine component, the energy of the hot gases is converted intowork, some of which may be used to drive the integral compressor througha rotating shaft, with the remainder available for useful work to drivea load such as a generator via a rotating shaft (e.g., an extension ofthe rotating shaft) for producing electricity. A number of gas turbinesystems may be employed in parallel within a power generation system. Ina combined cycle system, one or more steam turbine systems may also beemployed with the gas turbine system(s). In this setting, a hot exhaustgas from the gas turbine system(s) is fed to one or more heat recoverysteam generators (HRSG) to create steam, which is then fed to a steamturbine component having a separate or integral rotating shaft with thegas turbine system(s). In any event, the energy of the steam isconverted into work, which can be employed to drive a load such as agenerator for producing electricity.

When a power generation system is created, its parts are configured towork together to provide a system having a desired power output. Theability to increase power output on demand and/or maintain power outputunder challenging environmental settings is a continuous challenge inthe industry. For example, on hot days, the electric consumption isincreased, thus increasing power generation demand. Another challenge ofhot days is that as temperature increases, compressor flow decreases,which results in decreased generator output. One approach to increasepower output (or maintain power output, e.g., on hot days) is to addcomponents to the power generation system that can increase air flow tothe combustor of the gas turbine system(s). One approach to increase airflow is adding a storage vessel to feed the gas turbine combustor. Thisparticular approach, however, typically requires a separate power sourcefor the storage vessel, which is not efficient.

Another approach to increasing air flow is to upgrade the compressor.Currently, compressors have been improved such that their flow capacityis higher than their predecessor compressors. These new, higher capacitycompressors are typically manufactured to either accommodate new,similarly configured combustors, or older combustors capable of handlingthe increased capacity. A challenge to upgrading older gas turbinesystems to employ the newer, higher capacity compressors is that thereis currently no mechanism to employ the higher capacity compressors withsystems that cannot handle the increased capacity without upgradingother expensive parts of the system. Other parts that oftentimes need tobe upgraded simultaneously with a compressor upgrade include but are notlimited to the combustor, gas turbine component, generator, transformer,switchgear, HRSG, steam turbine component, steam turbine control valves,etc. Consequently, even though a compressor upgrade may be theoreticallyadvisable, the added costs of upgrading other parts renders the upgradeill-advised due to the additional expense.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides a power generation system,comprising: a generator; a gas turbine system for powering thegenerator, the gas turbine system including a turbine component, anintegral compressor and a combustor to which air from the integralcompressor and fuel are supplied, the combustor arranged to supply hotcombustion gases to the turbine component, and the integral compressorhaving a flow capacity greater than an intake capacity of at least oneof the combustor and the turbine component, creating an excess air flow;a supplemental gas turbine system including a supplemental combustorarranged to supply hot combustion gases to a supplemental turbinecomponent thereof, the supplemental turbine component operativelycoupled to a supplemental generator; and a first control valve systemcontrolling flow of the excess air flow along an excess air flow path,wherein the excess air flow path feeds the excess air flow to an intakeof the supplemental combustor, and the supplemental combustor combuststhe excess air flow with a fuel to create the hot combustion gases forthe supplemental turbine component.

A second aspect of the disclosure provides a method, comprising:powering a generator using a gas turbine system including a turbinecomponent, an integral compressor and a combustor to which air from theintegral compressor and fuel are supplied, the combustor arranged tosupply hot combustion gases to the turbine component, and the integralcompressor having a flow capacity greater than an intake capacity of atleast one of the combustor and the turbine component, creating an excessair flow; powering a supplemental generator using a supplemental gasturbine system including a supplemental combustor arranged to supply hotcombustion gases to a supplemental turbine component thereof, thesupplemental turbine component operatively coupled to the supplementalgenerator; and extracting the excess air flow from the gas turbinesystem and directing the excess air flow to an intake of thesupplemental combustor, the supplemental combustor combusting the excessair flow with a fuel to create the hot combustion gases for thesupplemental turbine component.

The illustrative aspects of the present disclosure are designed to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawing that depicts various embodiments of the disclosure, in which:

FIG. 1 shows a schematic diagram of a power generation system accordingto embodiments of the invention.

FIG. 2 shows a schematic diagram of a power generation system includingan eductor according to embodiments of the invention.

It is noted that the drawing of the disclosure is not to scale. Thedrawing is intended to depict only typical aspects of the disclosure,and therefore should not be considered as limiting the scope of thedisclosure. In the drawing, like numbering represents like elementsbetween the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the disclosure provides a power generation systemincluding a gas turbine system including a compressor that creates anexcess air flow. Embodiments of the invention provide ways to employ theexcess air flow to improve output and value of the power generationsystem.

Referring to FIG. 1, a schematic diagram of a power generation system100 according to embodiments of the invention is provided. System 100includes a gas turbine system 102. Gas turbine system 102 may include,among other components, a turbine component 104, an integral compressor106 and a combustor 108. As used herein, “integral” compressor 106 is sotermed as compressor 106 and turbine component 104 may be integrallycoupled together by, inter alia, a common compressor/turbine rotatingshaft 110 (sometimes referred to as rotor 110). This structure is incontrast to many compressors that are separately powered, and notintegral with turbine component 104.

Combustor 108 may include any now known or later developed combustorsystem generally including a combustion region and a fuel nozzleassembly. Combustor 108 may take the form of an annular combustionsystem, or a can-annular combustion system (as is illustrated in thefigures). In operation, air from integral compressor 106 and a fuel,such as natural gas, are supplied to combustor 108. Diluents may also beoptionally delivered to combustor 108 in any now known or laterdeveloped fashion. Air drawn by integral compressor 106 may be passedthrough any now known or later developed inlet filter housing 120. Asunderstood, combustor 108 is arranged to supply hot combustion gases toturbine component 104 by combustion of the fuel and air mixture. Inturbine component 104, the energy of the hot combustion gases isconverted into work, some of which may be used to drive compressor 106through rotating shaft 110, with the remainder available for useful workto drive a load such as, but not limited to, a generator 122 forproducing electricity, and/or another turbine via rotating shaft 110 (anextension of rotating shaft 110). A starter motor 112 such as but notlimited to a conventional starter motor or a load commutated inverter(LCI) motor (shown) may also be coupled to rotating shaft 110 forstarting of gas turbine system 102 in any conventional fashion. Turbinecomponent 104 may include any now known or later developed turbine forconverting a hot combustion gas flow into work by way of rotating shaft110.

In one embodiment, gas turbine system 102 may include a model MS7001FB,sometimes referred to as a 7FB engine, commercially available fromGeneral Electric Company, Greenville, S.C. The present invention,however, is not limited to any one particular gas turbine system and maybe implemented in connection with other systems including, for example,the MS7001FA (7FA) and MS9001FA (9FA) models of General ElectricCompany.

In contrast to conventional gas turbine system models, integralcompressor 106 has a flow capacity greater than an intake capacity ofturbine component 104 and/or first combustor 108. That is, compressor106 is an upgraded compressor compared to a compressor configured tomatch combustor 108 and turbine component 104. As used herein,“capacity” indicates a flow rate capacity. For example, an initialcompressor of gas turbine system 102 may have a maximum flow ratecapacity of about 487 kilogram/second (kg/s) (1,075 pound-mass/second(lbm/s)) and turbine component 104 may have a substantially equalmaximum flow capacity, i.e., around 487 kg/s. Here, however, compressor106 has replaced the initial compressor and may have an increasedmaximum flow capacity of, for example, about 544 kg/s (1,200 lbm/s),while turbine component 104 continues to have a maximum flow capacityof, e.g., around 487 kg/s. (Where necessary, starter motor 112 may alsohave been upgraded, e.g., to an LCI motor as illustrated, to accommodateincreased power requirements for startup of integral compressor 106).Consequently, turbine component 104 cannot take advantage of all of thecapacity of compressor 106, and an excess air flow 200 is created bycompressor 106 above a maximum capacity of, e.g., turbine component 104.Similarly, the flow capacity of integral compressor 106 may exceed themaximum intake capacity of combustor 108. In a similar fashion, thepower output of turbine component 104 if exposed to the full flowcapacity of integral compressor 106 could exceed a maximum allowed inputfor generator 122. While particular illustrative flow rate values havebeen described herein, it is emphasized that the flow rate capacitiesmay vary widely depending on the gas turbine system and the new, highcapacity integral compressor 106 employed. As will be described herein,the present invention provides various embodiments for power generationsystem 100 to employ the excess air flow in other parts of powergeneration system 100.

As also shown in FIG. 1, in one embodiment, power generation system 100may optionally take the form of a combined cycle power plant thatincludes a steam turbine system 160. Steam turbine system 160 mayinclude any now known or later developed steam turbine arrangement. Inthe example shown, high pressure (HP), intermediate pressure (IP) andlow pressure (LP) sections are illustrated; however, not all arenecessary in all instances. As known in the art, in operation, steamenters an inlet of the steam turbine section(s) and is channeled throughstationary vanes, which direct the steam downstream against bladescoupled to a rotating shaft 162 (rotor). The steam may pass through theremaining stages imparting a force on the blades causing rotating shaft162 to rotate. At least one end of rotating shaft 162 may be attached toa load or machinery such as, but not limited to, a generator 166, and/oranother turbine, e.g., a gas turbine system 102 or another gas turbinesystem. Steam for steam turbine system 160 may be generated by one ormore steam generators 168, i.e., heat recovery steam generators (HRSGs).HRSG 168 may be coupled to, for example, an exhaust 172 of gas turbinesystem 102. After passing through HRSG 168, the combustion gas flow, nowdepleted of heat, may be exhausted via any now known or later developedemissions control system 178, e.g., stacks, selective catalyticreduction (SCR) units, nitrous oxide filters, etc. While FIG. 1 shows acombined cycle embodiment, it is emphasized that steam turbine system160 including HRSG 168 may be omitted. In this latter case, exhaust 172would be passed directly to emission control system 178 or used in otherprocesses.

Power generation system 100 may also include any now known or laterdeveloped control system 180 for controlling the various componentsthereof. Although shown apart from the components, it is understood thatcontrol system 180 is electrically coupled to all of the components andtheir respective controllable features, e.g., valves, pumps, motors,sensors, gearing, generator controls, etc.

Returning to details of gas turbine system 102, as noted herein,integral compressor 106 has a flow capacity greater than an intakecapacity of turbine component 104 and/or combustor 108, which creates anexcess air flow 200. As illustrated, excess air flow 200 may be formedby extracting air from compressor 106. In one embodiment, a firstcontrol valve system 202 controls flow of excess air flow 200 along anexcess gas flow path 250 to a supplemental gas turbine system 272. Firstcontrol valve system 202 may include any number of valves necessary tosupply the desired excess air flow 200, e.g., one, two (as shown) ormore than two. In one embodiment, excess air flow 200 may be extractedfrom integral compressor 106 at a discharge 204 thereof using acompressor discharge control valve 206. That is, compressor dischargecontrol valve 206 controls a first portion of excess air flow 200 takenfrom discharge 204 of integral compressor 106. In this case, anotherupstream valve 210 may be omitted. In another embodiment, however,excess air flow 200 may be extracted at one or more stages of compressor106 where desired, e.g., at one or more locations upstream of discharge204, at discharge 204 and one or more locations upstream of thedischarge, etc., using appropriate valves and related control systems.In this case, first control valve system 202 may further include one ormore upstream control valves 210 controlling a second portion of excessair flow 200 taken from a stage(s) of integral compressor 106 upstreamfrom discharge 204. Any number of upstream control valve(s) 210 may beemployed in first control valve system 202 to provide any desired excessair flow 200 from integral compressor 106, i.e., with a desiredpressure, flow rate, volume, etc. Compressor discharge valve 210 can beomitted where other upstream control valve(s) 210 provide the desiredexcess air flow 200. First control valve system 202 may also include atleast one sensor 220 for measuring a flow rate of each portion of theexcess air flow, each sensor 220 may be operably coupled to a respectivecontrol valve or an overall control system 180. Control valve system 202may include any now known or later developed industrial control forautomated operation of the various control valves illustrated.

Excess air flow 200 eventually passes along an excess gas flow path 250,which may include one or more pipes, to a supplemental gas turbinesystem 272. Although illustrated as if excess air flow 200 is directedto supplemental gas turbine system 272 in a single conduit, it isunderstood that the excess air flow may be directed to one or morelocations of system 272. Supplemental gas turbine system 272 may includea supplemental combustor 274 arranged to supply hot combustion gases toa supplemental turbine component 276. Supplemental combustor 274 mayinclude any form of combustor described relative to combustor 108 thatis capable of using excess air flow 200 (or augmented excess gas flow270 (FIG. 2) (described herein)) to create and supply hot combustiongases for supplemental turbine component 276. Similarly, supplementalturbine component 276 may include any form of turbine componentdescribed relative to turbine component 104. As illustrated,supplemental turbine component 276 is operatively coupled to asupplemental generator 278, which may be referred to herein as a“supplemental generator” as it may be different than generator 122coupled to gas turbine system 102. Supplemental generator 278 may alsobe different than generator 166 of steam turbine system 160. In analternative embodiments, generator 274 may be the same as generator 122or generator 166. In any event, excess air flow 200 (or augmented excessgas flow 270 (FIG. 2)) may be employed to generate power viasupplemental gas turbine system 272, thus employing the excess capacityof integral compressor 106 in an efficient manner. An exhaust 280 ofsupplemental gas turbine system 272 may be delivered to an exhaust 172of turbine component 104 for use in creating steam in HRSG 168.

Referring to FIG. 2, power generation system 100 may also optionallyinclude an eductor 252 positioned in excess gas flow path 250 for usingexcess air flow 200 as a motive force to augment the excess air flowwith additional gas 254. Additional gas 254 with excess air flow 200form an augmented excess gas flow 270 that is delivered to supplementalgas turbine system 272. That is, augmented excess gas flow 270 issupplied to supplemental gas turbine system 272. Augmented excess gasflow 270 provides increased total air/gas mass to supplemental combustor274, and may allow for additional power to be generated using generator278. Additional mass flow to HRSG 168 via exhaust 280 may also berecognized, increasing HRSG 168 steam production.

Eductor 252 may take the form of any pump that uses a motive fluid flowto pump a suction fluid, i.e., additional gas 254. Here, eductor 252uses excess air flow 200 as a motive fluid to add additional gas 254 toexcess air flow 200, i.e., by suctioning in the additional gas, from anadditional gas source 256 along a suction side flow path 258. Additionalgas source 256 may take a variety of forms. In one embodiment,additional gas source 256 may take the form of inlet filter housing 120of integral compressor 106. In this case, suction side flow path 258 toeductor 252 may be coupled to inlet filter housing 120 of integralcompressor 106 (shown by dashed line) such that additional gas 254includes ambient air. Here, additional gas 254 is in the form of ambientair. In another embodiment, additional gas 254 may include ambient airfrom an additional gas source 256 other than inlet filter housing 120,e.g., another filter housing, air directly from the environment butlater filtered within flow path 258, etc. In either of theaforementioned embodiments, augmented excess gas flow 270 includesmostly air, i.e., it is an augmented excess air flow. In anotherembodiment, however, additional gas 254 may include a process gas suchas but not limited to synthesis (“syn-gas”) from a refinery,blast-furnace gas, methane from a waste pile/dump, etc. Additional gas254, in another embodiment, may also include exhaust from an engine,e.g., from a combustion engine, a diesel engine, another gas turbinesystem, etc. A second control valve system 260 may be provided insuction side flow path 258 for controlling a flow of additional gas 254into eductor 252. Second control valve system 260 may include a controlvalve 262 that may operate to control the amount of additional gas 254into eductor 252. Second control valve system 260 may also include atleast one sensor 220 for measuring a flow rate of additional gas 254 insuction side flow path 258, the sensor operably coupled to secondcontrol valve system 260 for measuring a flow rate of additional gas254.

As also illustrated, an exhaust 172 of turbine component 104 may be fedto HRSG 168 for creating steam for steam turbine system 160. Whereexhaust 280 of supplemental gas turbine system 272 is as hot as exhaust172 of turbine component 104 or hotter, it may be added to exhaust 172for more efficiently creating steam in HRSG 168. Where exhaust 280 ofsupplemental gas turbine system 272 is not hotter than exhaust 172 ofturbine component 104, it may be used to increase mass flow and to theHRSG 168 or elsewhere in power generation system 100 or exhausted by wayof emissions control system 178, skipping HRSG 168. As illustrated, HRSG168 may also feed steam to a co-generation steam load 170. Co-generationsteam load 170 may include, for example, steam to a petro-chemicalfacility, steam for district heating, steam for “tar-sands” oilextraction, etc.

With further regard to each control valve system 202, 260, each controlvalve thereof may be positioned in any position between open and closedto provide the desired partial flows to the stated components. Further,while one passage to each component is illustrated after each controlvalve, it is emphasized that further piping and control valves may beprovided to further distribute the respective portion of excess air flow200 to various sub-parts, e.g., numerous inlets to eductor 252, etc.Each sensor 220 may be operably coupled to control valve system(s) 202,260 and control system 180 for automated control in a known fashion.Other sensors 220 for measuring flow can be provided where necessarythroughout power generation system 100. Control valve systems 202, 260and hence flow of excess air flow 200 and operation of eductor 252 maybe controlled using any now known or later developed industrialcontroller, which may be part of an overall power generation system 100control system 180. Control system 180 may control operation of all ofthe various components of power generation system 100 in a knownfashion, including controlling control valve systems 202, 260.

Power generation system 100 including gas turbine system 102 havingintegral compressor 106 that creates an excess air flow 200 thatprovides a number of advantages compared to conventional systems. Forexample, compressor 106 may improve the power block peak, base andhot-day output of power generation system 100 at a lower cost relativeto upgrading all compressors in the system, which can be very expensivewhere a number of gas turbines are employed. In addition embodiments ofthe invention, reduce the relative cost of an upgraded compressor, i.e.,compressor 106, and in-turn improves the viability and desirability ofan upgraded compressor by providing a way to efficiently consume more ofthe excess air flow. Further, power generation system 100 includingintegral compressor 106 expands the operational envelope of system 100by improving project viability in the cases where any one or more of thefollowing illustrative sub-systems are undersized: turbine component104, generator 122, transformer (not shown), switchgear, HRSG 168, steamturbine system 160, steam turbine control valves, etc. In this fashion,system 100 provides an improved case to upgrade a single compressor in,for example, a single gas turbine and single steam turbine combinedcycle (1×1 CC) system as compared to the do-nothing case. Where eductor252 (FIG. 2), the aforementioned advantages of augmented excess gas flow270 to supplemental gas turbine system 272 such as additional mass flowand additional power generation may be recognized. Additional mass flowto HRSG 168 may also be achieved using eductor 252.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A power generation system, comprising: agenerator; a gas turbine system for powering the generator, the gasturbine system including a turbine component, an integral compressor, acombustor to which air from the integral compressor and fuel aresupplied, and a first rotatable shaft coupled to the gas turbine system,the combustor arranged to supply hot combustion gases to the turbinecomponent, and the integral compressor having a flow capacity greaterthan an intake capacity of at least one of the combustor and the turbinecomponent, creating an excess air flow; a supplemental gas turbinesystem including a second rotatable shaft and a supplemental combustorarranged to supply hot combustion gases of the supplemental combustor toa supplemental turbine component thereof, the supplemental turbinecomponent operatively coupled to a supplemental generator; a firstcontrol valve system controlling flow of the excess air flow along anexcess air flow path; and an eductor positioned in the excess air flowpath for using the excess air flow as a motive force to augment theexcess air flow with additional gas, the educator creating an augmentedexcess gas flow, wherein the excess air flow path feeds the augmentedexcess gas flow directly to the intake of the supplemental combustor,and the supplemental combustor combusts the augmented excess gas flowwith the fuel to create the hot combustion gases of the supplementalcombustor for the supplemental turbine component; wherein an exhaust ofthe turbine component feeds a heat recovery steam generator (HRSG) forcreating steam for a steam turbine system, the steam turbine systemincluding a third rotatable shaft; and wherein the first, second, andthird rotatable shafts are not within one another.
 2. The powergeneration system of claim 1, wherein the HRSG also feeds steam to aco-generation steam load.
 3. The power generation system of claim 1,wherein the first control valve system includes a compressor dischargecontrol valve controlling a first portion of the excess air flow takenfrom a discharge of the integral compressor, and an upstream controlvalve controlling a second portion of the excess air flow taken from astage of the integral compressor upstream from the discharge.
 4. Thepower generation system of claim 3, further comprising at least onesensor for measuring a flow rate of each portion of the excess air flow,each sensor operably coupled to a respective control valve.
 5. The powergeneration system of claim 1, wherein the eductor includes a suctionside flow path, and further comprising a second control valve system inthe suction side flow path controlling a flow of the additional gas intothe eductor.
 6. The power generation system of claim 5, wherein thesuction side flow path is fluidly coupled to an inlet filter of theintegral compressor.
 7. The power generation system of claim 1, furthercomprising a sensor for measuring a flow rate of the additional gas in asuction side flow path of the eductor, the sensor operably coupled tothe second control valve system.
 8. The power generation system of claim1, wherein a suction side flow path of the eductor is fluidly coupled toan inlet filter of the integral compressor.
 9. The power generationsystem of claim 1, wherein the generator that is different than thesupplement generator.
 10. The power generation system of claim 1,wherein the additional gas includes ambient air.
 11. The powergeneration system of claim 1, wherein the additional gas includes aprocess gas.
 12. The power generation system of claim 1, wherein theadditional gas includes a synthesis gas.
 13. The power generation systemof claim 1, wherein the additional gas includes exhaust from an engine.